Hypobarically-controlled artificial limb with detents for amputees

ABSTRACT

A hypobarically-controlled artificial limb for amputees includes an outer socket, a flexible, compressible inner socket within the outer socket with a cavity for receiving the residual limb, a space between the inner socket and the outer socket, a vacuum source connected to the cavity, a positive pressure source connected to the space, a regulator for controlling the vacuum source and positive pressure source, and a seal for making an airtight seal between the residual limb and the socket. Another embodiment includes a semi-compressible molding material in the space to mold to the contours of the residual limb under the influence of vacuum and/or positive pressure.

This is a continuation-in-part application of U.S. patent applicationSer. No. 98/506,911, filed July 26, 1995, now U.S. Pat. No. 5,549,709.

BACKGROUND OF THE INVENTION

The present invention relates to prosthetic devices and moreparticularly to a hypobarically-controlled artificial limb for amputees.

An amputee is a person who has lost part of an extremity or limb such asa leg or arm which commonly may be termed as a residual limb. Residuallimbs come in various sizes and shapes with respect to the stump. Thatis, most new amputations are either slightly bulbous or cylindrical inshape while older amputations that may have had a lot of atrophy aregenerally more conical in shape. Residual limbs may further becharacterized by their various individual problems or configurationsincluding the volume and shape of a stump and possible scar, skin graft,bony prominence, uneven limb volume, neuroma, pain, edema or soft tissueconfigurations.

Referring to FIGS. 1 and 2, a below the knee residual limb 10 is shownand described as a leg 12 having been severed below the knee terminatingin a stump 14. In this case, the residual limb 10 includes soft tissueas well as the femur 16, knee joint 18, and severed tibia 20 and fibula22. Along these bone structures surrounded by soft tissue are nervebundles and vascular routes which must be protected against externalpressure to avoid neuromas, numbness and discomfort as well as otherkinds of problems. A below the knee residual limb 10 has its stump 14generally characterized as being a more bony structure while an abovethe knee residual limb may be characterized as including more softtissue as well as the vascular routes and nerve bundles.

Referring to FIG. 2, amputees who have lost a part of their arm 26,which terminates in a stump 28 also may be characterized as havingvascular routes, nerve bundles as well as soft and bony tissues. Theresidual limb 10 includes the humerus bone 30 which extends from belowthe shoulder to the elbow from which the radius 34 and ulna 36 bones maypivotally extend to the point of severance. Along the humerus bone 30are the biceps muscle 38 and the triceps muscle 40 which still yet maybe connected to the radius 34 and the ulna 36, respectively.

In some respects, the residual limb amputee that has a severed arm 26does not have the pressure bearing considerations for an artificial limbbut rather is concerned with having an artificial limb that isarticulable to offer functions typical of a full arm, such as bending atthe elbow and grasping capabilities. An individual who has a paralyzedlimb would also have similar considerations wherein he or she woulddesire the paralyzed limb to have some degree of mobility and thusfunctionality.

Historically, artificial limbs typically used by a leg amputee were forthe most part all made out of wood such as an Upland Willow. The limbswere hand carved with sockets for receiving the stump 14 of the residuallimb 10. Below the socket would be the shin portion with the foot belowthe shin. These wooden artificial limbs were covered with rawhide whichoften were painted. The sockets of most wood limbs were hollow as thelimbs were typically supported in the artificial limb by thecircumferential tissue adjacent the stump 14 rather than at the distalend of the stump 14.

Some artificial limbs in Europe were also made from forged pieces ofmetal that were hollow. Fiber artificial limbs were also used which werestretched around a mold after which they were permitted to dry and cure.Again, these artificial limbs were hollow and pretty much supported theresidual limb about the circumferential tissue adjacent the stump 14.

All of these various artificial limbs have sockets to put the amputee'sstump 14 thereinto. There are generally two categories of sockets. Thereare hard sockets wherein the stump goes right into the socket actuallytouching the socket wall without any type of liner or stump sock.Another category of sockets is a socket that utilizes a liner or insert.Both categories of sockets typically were opened ended sockets wherethey had a hollow chamber in the bottom and no portion of the sockettouched the distal end of the stump 14. So, the stump was supportedabout its circumferential sides as it fits against the inside wall ofthe sockets.

These types of sockets caused a lot of shear force on the stump 14 aswell as had pressure or restriction problems on the nerve bundles andvascular flow of fluid by way of the circumferential pressure effect ofthe socket on the limb. This pressure effect could cause a swelling intothe ends of the socket where an amputee may develop severe edema anddraining nodules at the end of their stump 14.

With time, prosthetists learned that by filling in the socket's hollowchamber and encouraging a more total contact with the stump and thesocket, the swelling and edema problems could be eliminated. However,the problematic tissue configurations, such as bony prominences,required special consideration such as the addition of soft or pliablematerials to be put into the socket.

Today, most artificial limbs are constructed from thermoset plasticssuch as polyester resins, acrylic resins, polypropylenes andpolyethylenes, which are perhaps laminated over a nylon stockinettewhich also may be impregnated by the various resins.

In the past, most artificial limbs were suspended from the amputee'sbody by some form of pulley, belt or strap suspension often used withvarious harnesses and perhaps leather lacers or lacings. Another methodof suspending artificial limbs is known as the wedge suspension whereinan actual wedge is built into the socket which is more closed at its topopening. The wedge in the socket cups the medial femoral condyle orknuckle at the abductor tubical. Yet another form of suspension isreferred to as the shuttle system or a mechanical hookup or linkupwherein a thin suction liner is donned over the stump that has a dockingdevice on the distal end which mechanically links up with itscooperative part in the bottom of the socket chamber. Sleeve suspensionswere also used wherein the amputee may use a latex rubber tube whichforms into a rubber-like sleeve which would be rolled on over both thetop of the artificial limb and onto the amputee's thigh. The sleevesuspensions have been used in combination with other forms ofsuspensions techniques.

Both the use of a positive pressure system and the use of a negativepressure system (or hypobaric closed chamber) have been utilized in thefield of prosthetics. At one time, for pressure systems "inflatableinner tubes" were used to fit into sockets. Presently, there arepneumatic "bags" which are strategically placed over what peopleconsider to be good weight-bearing areas to increase pressure to helpaccommodate for volume changes within the socket.

The problem with this is that it is a very specific pressure and createsatrophy and loss of tissue dramatically over these high pressure areas.None of these systems employs positive pressure distributed over thetotal contact area between the residual limb and the artificial limbsocket to accommodate volume changes within the socket.

The negative pressure aspects have been utilized for a closed chamber inthat a socket is donned by pulling in with a sock, pulling the sock outof the socket and then closing the opening with a valve. This creates aseal at the bottom and the stump is held into the socket by thehypobaric seal. However, there are no systems that employ a negativepressure produced by a vacuum pump to lock the residual limb to theartificial limb.

The older systems were initially started in Germany. They were anopen-ended socket, meaning there was an air chamber in the bottom of thesocket. This did not work particularly well because it would causeswelling of the residual limb into the chamber created by the negativedraw of suspending the weight of the leg and being under a confinedarea. This would lead to significant edema which would be severe enoughto cause stump breakdown and drainage.

It was later discovered in America that total contact was essentialbetween the residual limb and the socket and once you had total contactthe weight was distributed evenly or the suspension was distributed overthe whole surface of the limb rather than just over the open chamberportion of the socket.

The human body as a whole is under approximately one atmosphere ofpressure at sea level. It keeps and maintains a normal fluid systemthroughout the body. When an amputee dons a prosthesis and begins takingthe pressures of transmitting the weight of the body through the surfacearea of the residual limb to the bone, there is increased pressure onthe residual limb equal to one atmosphere plus whatever additionalpressures are created by weight bearing. This increased pressure causesthe eventual loss of fluids within the residual limb to the largerportion of the body which is under less pressure. This loss of fluidscauses the volume of the residual limb to decrease during the day. Itvaries from amputee to amputee, but it is a constant among all amputeesand the more "fleshy" and the softer the residual limb, the more volumefluctuation there will be. The greater the weight and the smaller thesurface area, the greater the pressures will be and the more "swings"there will be in fluids. In the past, the amputee had to compensate forthis volume decrease by removing the artificial limb and donningadditional stump socks to make up for the decreased residual limbvolume.

While some of these devices addressed some of the problems associatedwith prosthetics, none of the artificial limbs, liners and sockets,individually or in combination, offered a prosthesis that presented atotal contact relationship with the residual limb; absorbed anddissipated shear, shock and mechanical forces transmitted to the limbtissues by the artificial limb; controlled residual limb volume; usednegative pressure as a locking device to hold the residual limb into thesocket; and used positive pressure not for specific weight bearing, butto totally adjust and adapt the internal socket environment.

There is a need for an improved hypobarically-controlled artificial limbthat will offer total contact relationship with the residual limb;absorb and dissipate shock, mechanical and shear forces typicallyassociated with ambulation, twisting and turning and weight bearing withan artificial limb; control residual limb volume by way of even weightdistribution; use negative pressure as a locking device to hold theresidual limb into the socket; use positive pressure to totally adjustand adapt the internal socket environment to changes in residual limbvolume; and control stump volume changes by cooperation between anegative pressure system and a positive pressure system.

In the past, artificial limbs had to be custom-built for the amputee.The custom building process generally consisted of: placing a singly plythin cotton casting sock over the residual limb; making a first negativemold of the residual limb by forming an orthopedic plaster wrap aboutthe residual limb and casting sock; matting a first positive model ofthe residual limb by filling the negative mold with plaster; forming athermoplastic foam about the positive model to create a space for aliner; adding additional thermoplastic foam to form a distal end cap aswell as other areas which may require additional thicknesses due totissue configurations; forming a second enlarged negative plaster moldabout the foam; removing the foam; pouring a liquid and moldable linerinto the space between the positive model and the second negative mold;allowing the liner to harden; removing the liner from the secondnegative mold; having the amputee don the liner over the residual limb;placing another single ply thin casting sock over the liner; making athird plaster wrap or negative mold of the artificial limb socket aboutthe residual limb and the liner; removing the liner from the thirdplaster wrap; making a plaster cast or positive model of the socket fromdental plaster; milling or shaving the positive model to create areduced positive model to create weight bearing areas and compression ofthe liner against the residual limb and the socket; and making thesocket from the reduced positive model.

This custom-building process is expensive, time-consuming, and requiresthe constant attention of a skilled prosthetist.

There is a need for a generic artificial limb socket which can be fittedto the contours of the residual limb without the need for a lengthy,expensive custom-molding process. The socket should contain asemi-compressible molding material which can be molded to the contoursof the residual limb under vacuum and/or positive air pressure.

SUMMARY OF THE INVENTION

A hypobarically-controlled artificial limb for amputees includes anouter socket, a flexible, compressible inner socket interlockable withinthe outer socket with a cavity for receiving the residual limb, a spacebetween the inner socket and the outer socket, a vacuum source connectedto the cavity, a positive pressure source connected to the space, aregulator for controlling the vacuum source and positive pressuresource, and a seal for making an airtight seal between the residual limband the socket. Another embodiment includes a semi-compressible moldingmaterial in the space to mold to the contours of the residual limb underthe influence of vacuum and/or positive pressure.

A principle object and advantage of the present invention is that ituses vacuum within the artificial limb socket to suspend the artificiallimb from the residual limb.

Another object and advantage of the present invention is that it usesvacuum within the artificial limb socket to compensate for socket fitand volumetric changes within the socket.

Another object and advantage of the present invention is that it usesvacuum within the socket to lock the residual limb into the socket whilepreventing negative draw within the socket from causing swelling of theresidual limb into the socket.

Another object and advantage of the present invention is that it usesvacuum within the socket to oppose the loss of fluids from the residuallimb caused by weight-bearing pressures.

Another object and advantage of the present invention is that it usespositive pressure within the socket to automatically reduce socketvolume to compensate for fluid loss in the residual limb.

Another object and advantage of the present invention is that it usesboth vacuum and positive pressure working together to lock the residuallimb into the socket and reduce socket volume to compensate for fluidloss in the residual limb.

Another object and advantage of the present invention is that both thevacuum and the positive pressure may be created by a miniaturized pumpwith a motor drive.

Another object and advantage of the present invention is that itincludes a digital computer system to control the miniaturized pump toregulate both negative pressure and positive pressure.

Another object and advantage of the present invention is that itincludes a semi-compressible molding material between the outer socketand the inner socket which may be molded to the contours of theartificial limb under the influence or vacuum and/or positive pressure,thereby avoiding the need for a custom-building process.

Mother object and advantage of the present invention is that the innersocket and outer socket are interlockable with each other to preventrelative movement. Advantageously, the interlocking is achieved by meansof a pair of detents, one on each socket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the tissue and skeletal structureof an amputee's residual limb;

FIG. 2 is a side elevational view of a residual limb in the form of anamputated arm showing the skeletal and muscular structure of theresidual limb;

FIG. 3 is an exploded elevational view of the residual limb donning thepolyurethane sleeve, stretchable nylon sleeve, liner, nylon sheath andsocket of an artificial limb;

FIG. 4 is a cross-section of the artificial limb in FIG. 3, which is afirst embodiment of the artificial limb.

FIG. 5 is a cross-section of the artificial limb similar to FIG. 4,showing a second embodiment of the artificial limb.

FIG. 6 is the same as FIG. 5, but showing compression of the innersocket under the influence of positive air pressure.

FIG. 7 is a cross-section of the artificial limb showing a thirdembodiment of the artificial limb.

FIG. 8 is a cross-section of the artificial limb showing a fourthembodiment of the artificial limb.

FIG. 9 is an elevational view of the polyurethane sleeve and secondstretchable nylon sleeve rolled over the socket and residual limb withclothing shown in broken outline.

FIG. 10 is a cross-section of the artificial limb showing a fifthembodiment of the artificial limb.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 3 shows the hypobarically-controlled artificial limb 50 of thepresent invention. The hypobarically-controlled artificial limb 50includes an outer socket 52, shin 54, and foot 56. The outer socket 52has a volume and shape to receive a substantial portion of the residuallimb 14 with a space 58 therebetween.

A first embodiment of the hypobarically-controlled artificial limb 50 isshown in FIG. 4. The hypobarically-controlled artificial limb 50 furtherincludes a flexible inner socket 60 with a cavity 62 with a volume andshape for receiving a substantial portion of the residual limb 14 andfitting in the space 58 between the outer socket 52 and the residuallimb 14. The inner socket 60 has an inner surface 64 opposing theresidual limb 14 and an outer surface 66 opposing the outer socket 52.

A vacuum source 70 may conveniently be attached to the shin 54. Thevacuum source 70 may preferably be a motor-driven pump 72. The vacuumsource 70 is connected to a power source 83, which may be a battery.

A vacuum valve 74 is suitably connected to the vacuum source 70. Thevacuum valve 74 may preferably be disposed on the outer socket 52. Avacuum tube 76 connects the vacuum valve 74 to the cavity 62. It will beseen that the vacuum source will cause the residual limb 14 to be drawninto firm contact with the inner surface 64 of the inner socket 60.

The hypobarically-controlled artificial limb 50 also includes aregulator means 80 for controlling the vacuum source 70. Preferably, theregulator means 80 may be a digital computer 82. Alternately, theregulator means may be a vacuum regulator. The regulator means 80 isconnected to a power source 83, which may be a battery.

A seal means 84 makes an airtight seal between the residual limb 14 andthe outer socket 52. Preferably, the seal means 84 is a nonfoamed,nonporous polyurethane suspension sleeve 86 which rolls over and coversthe outer socket 52 and a portion of the residual limb 14.Alternatively, the seal means 84 may be any type of seal which isairtight.

The hypobarically-controlled artificial limb 50 may also include a thinsheath 90 between the residual limb 14 and the inner surface 64 of theinner socket 60. As vacuum is applied to the cavity 62, the sheath 90will allow the vacuum to be evenly applied throughout the cavity 62.Without the sheath 90, the residual limb 14 might "tack up" against theinner surface 64 and form a seal which might prevent even application ofthe vacuum to the cavity 62. The sheath 90 may also be used to assistthe amputee into a smooth and easy fitting into the inner socket 60. Thesheath 90 is preferably made of thin knitted nylon.

The hypobarically-controlled artificial limb 50 may also include anonfoamed, nonporous polyurethane liner 92 receiving the residual limb14 and disposed between the sheath 90 and the residual limb 14. Theliner 92 provides a total-contact hypobaric suction, equal weightdistribution socket liner. The liner 92 readily tacks up to the skin ofthe residual limb 14 and provides total contact with the limb 14. Theliner 92 absorbs and dissipates shock, mechanical and shear forcestypically associated with ambulation.

The hypobarically-controlled artificial limb 50 may also include astretchable nylon second sleeve 94 for rolling over and covering thesuspension sleeve 86 to prevent clothing from sticking to and catchingthe suspension sleeve 86.

Referring to FIG. 3, the polyurethane tubular sleeve 86 may beappreciated alone and in combination with the urethane liner 92 togetherwith the optional nylon sheath 90 and second stretchable nylon sleeve94.

More specifically, the amputee takes the stretchable nylon second sleeve94, suitably made of a spandex-like material and rolls it up over thestump 14 to the upper portions of the residual limb suitably as thethigh of a leg 12. Next, the polyurethane sleeve 86 is also rolledupwardly over the residual limb 10. Thereafter, the liner 92 isoptionally donned.

Next, the amputee may optionally utilize the nylon sheath 90 which issuitably of a nonstretching, thin, friction reducing nylon. As stated,this sheath 90 optionally may be used to assist the amputee into asmooth and easy fitting into the inner socket 60. Alternatively, thesheath 90 may be avoided and the liner 92 simply inserted into the innersocket 60 of the artificial limb 50.

Next, the amputee simply grasps the rolled over portion of thepolyurethane sleeve 86 and rolls it over a substantial portion of theouter socket 52. The sleeve 86 makes an airtight seal between theresidual limb 14 and the outer socket 52.

As can be appreciated, the polyurethane sleeve 86 is tacky.Consequently, the stretchable nylon second sleeve 94 may be utilized androlled over the polyurethane sleeve 86.

The amputee then sets the regulator means 80 to cause the vacuum source70 to apply vacuum through the vacuum valve 74 and vacuum tube 76 to thecavity 62. Enough vacuum is applied to cause the residual limb (withoptional coverings) to be drawn firmly against the inner surface 64 ofthe inner socket 60, which is flexible. The vacuum source 70 maypreferably maintain a vacuum in the range of 0 to 25 inches of mercury.

It will be seen that the vacuum within the inner socket 60 will causethe hypobarically-controlled artificial limb 50 to be suspended from theresidual limb 14. The vacuum will lock the residual limb 14 into theinner socket 60 without causing swelling of the residual limb into thesocket, because of the total contact of the residual limb 14 with theinner socket 60. That is, there is no open chamber between the residuallimb 14 and the inner socket 60 which would draw on the residual limb.

As the volume of the residual limb 14 decreases during the day due toweight-bearing pressures, the regulator means 70 may appropriatelyadjust the vacuum source 70 to draw the residual limb 14 more firmlyagainst the inner socket 60 and thus compensate for the loss of residuallimb volume. The vacuum may also partially oppose the loss of fluidsfrom the residual limb caused by weight-bearing pressures.

A second embodiment of the hypobarically-controlled artificial limb 50is shown in FIGS. 5 and 6. The second embodiment of thehypobarically-controlled artificial limb 50 is as described above, withthe exception that the inner socket 60A is compressible as well as beingflexible. Instead of a vacuum source, the second embodiment has apositive air pressure source 100, which may preferably be a motor-drivenpump 102. The regulator means 80, which may be a digital computer 82,controls the positive air pressure source 100. The regulator means andpositive air pressure source 100 are connected to a power source 83,which may be a battery. A positive pressure valve 104 connects the space58 to the positive air pressure source 100, for compressing the innersocket 60A as the volume of the residual limb decreases.

It will be seen that as the volume of the residual limb 14 decreasesduring the day due to weight-bearing pressures, the regulator means 80may control the positive air pressure source 100 to cause air pressureto compress the inner socket 60A to compensate for the decreased volumeof the residual limb, as shown in FIG. 6.

A third embodiment of the hypobarically-controlled artificial limb 50 isshown in FIG. 7. The third embodiment is a combination of the first andsecond embodiments described above.

The motor-driven pump 72 may act as both the vacuum source 70 and thepositive air pressure source 100. The regulator means 80, vacuum source70 and positive air pressure source 100 are connected to a power source83, which may be a battery.

The vacuum source 70, under control of the regulator means 80, willcompensate for reduced residual limb volume up to a certain point. Fromthat point on, the regulator means 80 will cause the positive airpressure source 100 to further compensate for reduced residual limbvolume as described above. The third embodiment thus uses both vacuumand positive air pressure working together to lock the residual limb 14into the inner socket 60 and reduce socket volume to compensate forfluid loss in the residual limb 14. The exact point at which thechangeover is made between vacuum compensation and positive air pressurecompensation is controlled by the regulator means 80, which as describedmay be a digital computer appropriately programmed for the socketenvironment.

A fourth embodiment of the hypobarically-controlled artificial limb 50is shown in FIG. 8. The fourth embodiment is like the first embodiment,but includes two vacuum valves: a first vacuum valve 106 and a secondvacuum valve 110, both connected to the vacuum source 70. The firstvacuum valve 106 connects the vacuum source 70 to the space 58. Thespace 58 contains a semi-compressible material 108, such as polystyrenebeads, as disclosed in U.S. Pat. No. 4,828,325, herein incorporated byreference.

To don the artificial limb 50, the amputee proceeds as described above.After inserting the residual limb 14 (with optional coverings) into theinner socket 60B, which is both compressible and expandable, and rollingthe suspension sleeve 86 over the outer socket 52, the amputee activatesthe regulator means 80, causing the vacuum source 70 to apply a vacuumto the space 58. This causes the material 108 to lock mechanicallytogether into a rigid mass, conforming to the shape of the residual limb14. The inner socket 60B may expand slightly under the weight of theresidual limb 14 and under the influence of vacuum.

It will be seen that the semi-compressible molding material 108 can bemolded to the contours of the residual limb 14 without using acustom-building process to produce a custom socket. The outer socket 52may appropriately occur in standard sizes, such as small, medium, andlarge. The inner socket 60B may also occur in standard sizes such assmall, medium, and large. Adaptation of the inner socket 60B to thecontours of the residual limb 14 occurs through solidifying the material108 under the influence of vacuum.

The second vacuum valve 110 connects the vacuum source 70 to the cavity62 as previously described, for locking the residual limb 14 into theinner socket 60B.

The fourth embodiment may also include a positive air pressure source100 as previously described, to adjust the size of the inner socket 60Bto compensate for decreased residual limb volume.

The fourth embodiment may also include a thin sheath 90, liner 92, andsecond sleeve 94, as previously described.

The positive air pressure source 100 may also be used for shockabsorption and a dynamic response in the ankle and foot sections of theartificial limb 50, by means of a connection 120.

A fifth embodiment of the hypobarically controlled artificial limb 50 isshown in FIG. 10. This embodiment is the same as the first embodimentshown in FIG. 4, with some changes. First, vacuum source 71 may be ahand-operated vacuum pump 71 which may remove air from the cavity 62down to 25 inches of mercury but more commonly down by three to sixinches of mercury. A suitable hand-operated vacuum pump is marketedunder the trademark MITY VAC II® by Neward Enterprises, Inc. ofCucamonga, Calif.

The fifth embodiment also includes the seal means 84 which preferablyconsists of a non-foamed, nonporous polyurethane suspension sleeve 86for rolling over and covering a portion of the residual limb 14. Aportion of the seal means 86 is adapted to be disposed between the outersocket 52 and the inner socket 60. The sleeve may be made of any of avariety of air-impervious elastomers.

The fifth embodiment, shown in FIG. 10, also includes a mechanicalinterlock 67, 59 for interlocking the inner socket 62 with the outersocket 52. Preferably, the mechanical interlock consists of a firstdetent 67 in the inner socket 62 and a second detent 59 in the outersocket 52. The first detent 67 engages the second detent 59 to lock theinner socket 60 into the outer socket 52.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof, and it istherefore desired that the present embodiment be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than to the foregoing description to indicatethe scope of the invention.

What is claimed:
 1. A hypobarically-controlled artificial limb foramputees who have a residual limb, the artificial limb comprising:(a) anouter socket with a volume and shape to receive a substantial portion ofthe residual limb with a space therebetween; (b) an inner socket with acavity having a volume and shape for receiving a substantial portion ofthe residual limb and fitting in said space between said outer socketand the residual limb, said inner socket having an inner surface and anouter surface, said inner surface adapted to receive and support theresidual limb, said outer surface opposing said outer socket; (c) avacuum source; and (d) a vacuum valve connected to said vacuum sourceand in flow communication with said cavity to thereby facilitate drawingof the residual limb into firm contact with said inner surface of saidinner socket.
 2. The hypobarically-controlled artificial limb of claim1, further comprising a seal means for making an airtight seal betweenthe residual limb and one of said outer and inner sockets.
 3. Thehypobarically-controlled artificial limb of claim 1, further comprisinga thin sheath to be disposed between the residual limb and said innersurface of said inner socket.
 4. The hypobarically-controlled artificiallimb of claim 3, further comprising a nonfoamed, nonporous polyurethaneliner for receiving the residual limb and to be disposed between saidsheath and the residual limb.
 5. The hypobarically-controlled artificiallimb of claim 3, wherein said sheath is thin knitted nylon.
 6. Thehypobarically-controlled artificial limb of claim 1, wherein said vacuumsource is a hand-operated vacuum pump.
 7. The hypobarically-controlledartificial limb of claim 2, wherein said seal means comprises anonfoamed, nonporous polyurethane suspension sleeve for rolling over andcovering said outer socket and a portion of the residual limb, therebyforming an airtight seal.
 8. The hypobarically-controlled artificiallimb of claim 2, wherein said seal means comprises a nonfoamed,nonporous polyurethane suspension sleeve for rolling over and covering aportion of the residual limb, and a portion of said suspension sleevebeing adapted to be disposed between said outer socket and said innersocket.
 9. The hypobarically-controlled artificial limb of claim 7,further comprising a stretchable nylon second sleeve for rolling overand covering said suspension sleeve to prevent clothing from sticking toand catching said suspension sleeve.
 10. The hypobarically-controlledartificial limb of claim 1, further comprising a mechanical interlockfor interlocking said inner socket with said outer socket.
 11. Thehypobarically-controlled artificial limb of claim 10, wherein saidmechanical interlock further comprises a first detent in said innersocket and a second detent in said outer socket, said first detentengaging said second detent for locking said inner socket to said outersocket.
 12. A hypobarically-controlled artificial limb for amputees whohave a residual limb, the artificial limb comprising:(a) an outer socketwith a volume and shape to receive a substantial portion of the residuallimb with a space therebetween; (b) an inner socket removable from saidouter socket with a cavity having a volume and shape for receiving asubstantial portion of the residual limb and fitting in said spacebetween said outer socket and the residual limb, said inner sockethaving an inner surface and an outer surface, said inner surface adaptedto receive and support the residual limb, said outer surface opposingsaid outer socket; (c) a vacuum source; (d) a vacuum valve connected tosaid vacuum source and in flow communication with said cavity to therebyfacilitate drawing of the residual limb into firm contact with saidinner surface of said inner socket; and (e) a mechanical interlock forinterlocking said inner socket with said outer socket.
 13. Thehypobarically-controlled artificial limb of claim 12, wherein saidmechanical interlock further comprises a first detent in said innersocket and a second detent in said outer socket, said first detentengaging said second detent for locking said inner socket to said outersocket.
 14. The hypobarically-controlled artificial limb of claim 12,further comprising a seal means for making an airtight seal between theresidual limb and one of said outer and inner sockets.
 15. Thehypobarically-controlled artificial limb of claim 12, further comprisinga thin sheath to be disposed between the residual limb and said innersurface of said inner socket.
 16. The hypobarically-controlledartificial limb of claim 15, further comprising a nonfoamed, nonporouspolyurethane liner for receiving the residual limb and to be disposedbetween said sheath and the residual limb.
 17. Thehypobarically-controlled artificial limb of claim 15, wherein saidsheath is thin knitted nylon.
 18. The hypobarically-controlledartificial limb of claim 12, wherein said vacuum source is ahand-operated vacuum pump.
 19. The hypobarically-controlled artificiallimb of claim 14, wherein said seal means comprises a nonfoamed,nonporous polyurethane suspension sleeve for rolling over and coveringsaid outer socket and a portion of the residual limb, thereby forming anairtight seal.
 20. The hypobarically-controlled artificial limb of claim14, wherein said seal means comprises a nonfoamed, nonporouspolyurethane suspension sleeve for rolling over and covering a portionof the residual limb, and a portion of said suspension sleeve beingadapted to be disposed between said outer socket and said inner socket.21. The hypobarically-controlled artificial limb of claim 19, furthercomprising a stretchable nylon second sleeve for rolling over andcoveting said suspension sleeve to prevent clothing from sticking to andcatching said suspension sleeve.
 22. A hypobarically-controlledartificial limb for amputees who have a residual limb, the artificiallimb comprising:(a) an outer socket with a volume and shape to receive asubstantial portion of the residual limb with a space therebetween; (b)an inner socket with a cavity having a volume and shape for receiving asubstantial portion of the residual limb and fitting in said spacebetween said outer socket and the residual limb, said inner sockethaving an inner surface and an outer surface, said inner surface adaptedto receive and support the residual limb, said outer surface opposingsaid outer socket; (c) a vacuum source; (d) a vacuum valve connected tosaid vacuum source and in flow communication with said cavity to therebyfacilitate drawing of the residual limb into firm contact with saidinner surface of said inner socket; and (e) a seal means for making anairtight seal between the residual limb and one of said outer socket andsaid inner socket.
 23. The hypobarically-controlled artificial limb ofclaim 22, further comprising a thin sheath to be disposed between theresidual limb and said inner surface of said inner socket.
 24. Thehypobarically-controlled artificial limb of claim 23, further comprisinga nonfoamed, nonporous polyurethane liner for receiving the residuallimb and to be disposed between said sheath and the residual limb. 25.The hypobarically-controlled artificial limb of claim 23, wherein saidsheath is thin knitted nylon.
 26. The hypobarically-controlledartificial limb of claim 22, wherein said vacuum source is ahand-operated vacuum pump.
 27. The hypobarically-controlled artificiallimb of claim 22, wherein said seal means comprises a nonfoamed,nonporous polyurethane suspension sleeve for rolling over and coveringsaid outer socket and a portion of the residual limb, thereby forming anairtight seal.
 28. The hypobarically-controlled artificial limb of claim22, wherein said seal means comprises a nonfoamed, nonporouspolyurethane suspension sleeve for rolling over and covering a portionof the residual limb, and a portion of said suspension sleeve beingadapted to be disposed between said outer socket and said inner socket.29. The hypobarically-controlled artificial limb of claim 27, furthercomprising a stretchable nylon second sleeve for rolling over andcovering said suspension sleeve to prevent clothing from sticking to andcatching said suspension sleeve.
 30. The hypobarically-controlledartificial limb of claim 22, further comprising a mechanical interlockfor interlocking said inner socket with said outer socket.
 31. Thehypobarically-controlled artificial limb of claim 30, wherein saidmechanical interlock further comprises a first detent in said innersocket and a second detent in said outer socket, said first detentengaging said second detent for locking said inner socket to said outersocket.
 32. A hypobarically-controlled artificial limb for amputees whohave a residual limb, the artificial limb comprising:(a) an outer socketwith a volume and shape to receive a substantial portion of the residuallimb with a space therebetween; (b) an inner socket removable from saidouter socket with a cavity having volume and shape for receiving asubstantial portion of the residual limb and fitting in said spacebetween said outer socket and the residual limb, said inner sockethaving an inner surface and an outer surface, said inner surface adaptedto receive and support the residual limb, said outer surface opposingsaid outer socket; (c) a vacuum source; (d) a vacuum valve connected tosaid vacuum source and in flow communication with said cavity to therebyfacilitate drawing of the residual limb into firm contact with saidinner surface of said inner socket; (e) a seal means for making anairtight seal between the residual limb and one of said outer socket andsaid inner socket; and (f) a mechanical interlock for interlocking saidinner socket with said outer socket.
 33. The hypobarically-controlledartificial limb of claim 32, further comprising a thin sheath to bedisposed between the residual limb and said inner surface of said innersocket.
 34. The hypobarically-controlled artificial limb of claim 33,further comprising a nonfoamed, nonporous polyurethane liner forreceiving the residual limb and to be disposed between said sheath andthe residual limb.
 35. The hypobarically-controlled artificial limb ofclaim 33, wherein said sheath is thin knitted nylon.
 36. Thehypobarically-controlled artificial limb of claim 32, wherein saidvacuum source is a hand-operated vacuum pump.
 37. Thehypobarically-controlled artificial limb of claim 32, wherein said sealmeans comprises a nonfoamed, nonporous polyurethane suspension sleevefor rolling over and covering said outer socket and a portion of theresidual limb, thereby forming an airtight seal.
 38. Thehypobarically-controlled artificial limb of claim 32, wherein said sealmeans comprises a nonfoamed, nonporous polyurethane suspension sleevefor rolling over and covering a portion of the residual limb, and aportion of said suspension sleeve being adapted to be disposed betweensaid outer socket and said inner socket.
 39. Thehypobarically-controlled artificial limb of claim 37, further comprisinga stretchable nylon second sleeve for rolling over and covering saidsuspension sleeve to prevent clothing from sticking to and catching saidsuspension sleeve.